I found some wooden eggs at a local craft store and covered them in chocolate brown chalkboard paint. And they have kept my 2 year old entertained all day long (well, at least for a good hour). They look great plain too... like chocolate eggs.
Simple to make- just get yourself some chalkboard paint (it comes in all colors, just like egg dying) and some wooden eggs. Cover them in about 3 coats of paint, let dry, cover the egg in chalk then wipe clean for sealing.
If you don't want to do the work I put up a few in the shop here.